共查询到20条相似文献,搜索用时 31 毫秒
1.
Judd-Oflet analysis of spectrum and laser performance of Ho:YAP crystal end-pumped by 1.91μm Tm:YLF laser 下载免费PDF全文
The Ho:YAP crystal is grown by the Czochralski technique.The room temperature polarized absorption spectra of Ho:YAP crystal was measured on a c cut sample with 1 at% holmium.According to the obtained Judd-Ofelt intensity parameters Ω2 = 1.42 × 10-20 cm2,Ω4 = 2.92 × 10-20 cm2,and Ω6 = 1.71 × 10-20 cm2,this paper calculated the fluorescence lifetime to be 6 ms for 5I7 →5 I8 transition,and the integrated emission cross section to be 2.24×10-18 cm2.It investigates the room temperature Ho:YAP laser end pumped by a 1.91 μm Tm:YLF laser.The maximum output power was 4.1 W when the incident 1.91 μm pump power was 14.4 W.The slope efficiency is 40.8%,corresponding to an optical to optical conversion efficiency of 28.4%.The Ho:YAP output wavelength was centred at 2118 nm with full width at half maximum of about 0.8 nm. 相似文献
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Josué De-Santiago Iván E. Sánchez G. David Tamayo 《General Relativity and Gravitation》2018,50(8):101
In this work we study a phenomenological non-gravitational interaction between dark matter and dark energy. The scenario studied in this work extends the usual interaction model proportional to the derivative of the dark component density adding to the coupling a non-linear term of the form \(Q = \rho '/3(\alpha + \beta \rho _{Dark})\) This dark sector interaction model could be interpreted as a particular case of a running vacuum model of the type \(\Lambda (H) = n_0 + n_1 H^2 + n_2 H^4\) in which the vacuum decays into dark matter. For a flat FRW Universe filled with dark energy, dark matter and decoupled baryonic matter and radiation we calculate the energy density evolution equations of the dark sector and solve them. The different sign combinations of the two parameters of the model show clear qualitative different cosmological scenarios, from basic cosmological insights we discard some of them. The linear scalar perturbation equations of the dark matter were calculated. Using the CAMB code we calculate the CMB and matter power spectra for some values of the parameters \(\alpha \) and \(\beta \) and compare it with \(\Lambda \)CDM. The model modify mainly the lower multipoles of the CMB power spectrum remaining almost the same the high ones. The matter power spectrum for low wave numbers is not modified by the interaction but after the maximum it is clearly different. Using observational data from Planck, and various galaxy surveys we obtain the constraints of the parameters, the best fit values obtained are the combinations \(\alpha = (3.7 \pm 7 )\times 10^{-4} \), \(-\,(1.5\times 10^{-5}\, \mathrm{eV}^{-1})^{4} \ll \beta < (0.07\,\mathrm{eV}^{-1})^4\). 相似文献
4.
A. S. Zhevlakov A. E. Dorokhov A. E. Radzhabov 《Physics of Particles and Nuclei Letters》2011,8(7):768-771
The correction to anomalous magnetic momentum muon from the light by light scattering diagram with intermediate pion is calculated
in framework nonlocal chiral quark model. To fix the model parameters it is suggested to use the values of mass and two photon
width of the neutral pion. The value of the correction is in region am p0 , LbL = (5.05 ±0.03) ×10 - 10a_\mu ^{\pi ^0 , LbL} = (5.05 \pm 0.03) \times 10^{ - 10} for different set of model parameters. 相似文献
5.
S. F. Biagi M. Bourquin R. M. Brown H. J. Burckhart Ch. Doré P. Extermann M. Gailloud C. N. P. Gee W. M. Gibson R. J. Gray P. Jacot-Guillarmod P. W. Jeffreys W. C. Louis T. Modis P. Mühlemann R. C. Owen J. Perrier K. J. S. Ragan Ph. Rosselet B. J. Saunders P. Schirato H. W. Siebert V. J. Smith K. -P. Streit J. J. Thresher R. Weill A. T. Wood C. Yanagisawa 《Zeitschrift fur Physik C Particles and Fields》1985,28(4):495-507
In an experiment performed in the CERN SPS hyperon beam we have obtained a value for the branching ratio $${{\Sigma ^ + \to p\gamma } \mathord{\left/ {\vphantom {{\Sigma ^ + \to p\gamma } {\Sigma ^ + \to p\pi }}} \right. \kern-\nulldelimiterspace} {\Sigma ^ + \to p\pi }}^0 of\left( {2.46_{ - 0.35}^{ + 0.30} } \right) \times 10^{ - 3} ,$$ corresponding to a branching ratio $${{\Sigma ^ + \to p\gamma } \mathord{\left/ {\vphantom {{\Sigma ^ + \to p\gamma } {\Sigma ^ + \to all}}} \right. \kern-\nulldelimiterspace} {\Sigma ^ + \to all}}of\left( {1.27_{ - 0.18}^{ + 0.16} } \right) \times 10^{ - 3} .$$ This result is discussed in the context of present understanding of hyperon radiative decays. 相似文献
6.
This paper investigates the infrared absorption spectra of oxygen-related complexes in silicon crystals irradiated with
electron (1.5~MeV) at 360~K. Two groups of samples with low [Oi]=6.9× 1017~cm-3 and high [ Oi]=1.06× 1018~cm-3 were used. We found that the
concentration of the VO pairs have different behaviour to the
annealing temperature in different concentration of oxygen specimen,
it is hardly changed in the higher concentration of oxygen specimen. It
was also found that the concentration of VO2 in lower concentration
of oxygen specimen gets to maximum at 450~℃ and then
dissapears at 500~℃, accompanied with the appearing of
VO3. For both kinds of specimens, the concentration of VO3
reachs to maximum at 550~℃ and does not disappear
completely at 600~℃. 相似文献
7.
C. Q. Geng Y. K. Hsiao Chia-Wei Liu Tien-Hsueh Tsai 《The European Physical Journal C - Particles and Fields》2018,78(7):593
We explore the breaking effects of the SU(3) flavor symmetry in the singly Cabibbo-suppressed anti-triplet charmed baryon decays of \(\mathbf{B}_c\rightarrow \mathbf{B}_n M\), with \(\mathbf{B}_c=(\Xi _c^0,\Xi _c^+,\Lambda _c^+)\) and \(\mathbf{B}_n(M)\) the baryon (pseudo-scalar) octets. We find that these breaking effects can be used to account for the experimental data on the decay branching ratios of \({\mathcal {B}}(\Lambda _c^+\rightarrow \Sigma ^{0} K^{+},\Lambda ^{0} K^{+})\) and \(R'_{K/\pi }={\mathcal {B}}(\Xi ^0_c \rightarrow \Xi ^- K^+)\)/\({\mathcal {B}}(\Xi ^0_c \rightarrow \Xi ^- \pi ^+)\). In addition, we obtain that \({\mathcal {B}}(\Xi _{c}^{0} \rightarrow \Xi ^{-} K^{+},\Sigma ^{-} \pi ^{+})=(4.6 \pm 1.7,12.8 \pm 3.1)\times 10^{-4}\), \({\mathcal {B}}(\Xi _c^0\rightarrow pK^-,\Sigma ^+\pi ^-)=(3.0 \pm 1.0, 5.2 \pm 1.6)\times 10^{-4}\) and \({\mathcal {B}}(\Xi _c^+\rightarrow \Sigma ^{0(+)} \pi ^{+(0)})=(10.3 \pm 1.7)\times 10^{-4}\), which all receive significant contributions from the breaking effects, and can be tested by the BESIII and LHCb experiments. 相似文献
8.
The photo-degradation of green-, yellow-, orange- and red-emitting CdTe nanocrystals (NCs) in sol–gel SiO2 films was investigated quantitatively by measuring the PL efficiency as a function of the irradiation intensity. The degradation
behaviors of the NCs depended strongly on the particle size and the surface state. Green- and yellow-emitting CdTe NCs exhibited
a red-shifted PL peak wavelength and decreased PL efficiency after irradiation. In contrast, the PL peak wavelength of red-emitting
CdTe NCs remained unchange and their PL efficiency increased. Furthermore, the degraded degree of green-emitting NCs depended
linearly on the irradiation intensity
( \textrate \textconstant k1 = ( 1.10±0.04 ) ×10 - 6 \textphoton ) \left( {{\text{rate}}\,{\text{constant}}\,{k_{{1}}} = \left( {{1}.{1}0\pm 0.0{4}} \right) \times {1}{0^{{ - {6}}}}\,{\text{photon}}} \right) , whereas hat of red-emitting NCs showed a quadratic dependence
( \textrate \textconstant k2 = ( 2.26±0.1 ) ×10 - 26( \textc\textm2 \texts )/\textphoton ) \left( {{\text{rate}}\,{\text{constant}}\,{k_{{2}}} = \left( {{2}.{26}\pm 0.{1}} \right) \times {1}{0^{{ - {26}}}}\left( {{\text{c}}{{\text{m}}^{{2}}}\,{\text{s}}} \right)/{\text{photon}}} \right) at room temperature. This is ascribed to the different surface state of green- and red-emitting CdTe NCs. 相似文献
9.
Diffusion of W in the 723–1153 K temperature range both in paramagnetic and ferromagnetic α-Fe was studied, diffusion couples were manufactured by W evaporation onto high-purity Fe samples. Measurements were made
using the Heavy Ion Rutherford Backscattering (HIRBS) technique as the analysis tool. A straight Arrhenius plot was obtained
in the paramagnetic region with a break at the Curie temperature (1043 K) followed by a curved plot at lower temperatures
as a product of the effect of ferromagnetism on diffusion. A straight Arrhenius plot was obtained in the paramagnetic region
with a break at the Curie temperature (1043 K) followed by a curved plot at lower temperatures resulting from the effect of
ferromagnetism on diffusion. A previous developed model for the diffusion of non-magnetic impurities in ferromagnetic Fe fits
the data perfectly well, giving a temperature dependent diffusivity according to
$\everymath{\displaystyle}{rcl}D(T) &=& 2.3 \times 10^{- 6}\\[5pt]&&{}\times \exp \biggl[ - \frac{( 215~\mathrm{kJ}\,\mathrm{mol}^{-1} )\!\times\! ( 1 + 0.176s^{2} )}{RT} \biggr]~\mathrm{m}^{2}\,\mathrm{s}^{-1}$\everymath{\displaystyle}\begin{array}{rcl}D(T) &=& 2.3 \times 10^{- 6}\\[5pt]&&{}\times \exp \biggl[ - \frac{( 215~\mathrm{kJ}\,\mathrm{mol}^{-1} )\!\times\! ( 1 + 0.176s^{2} )}{RT} \biggr]~\mathrm{m}^{2}\,\mathrm{s}^{-1}\end{array} 相似文献
10.
The chirality-asymmetry macroscopic force mediated by light
pseudoscalar particles between α -quartz and some achiral
matter is studied. If this force between achiral source mass and
α -quartz with some chirality is attractive, it will become
repulsive when the chirality of the α -quartz crystal is
changed. According to the tested limits of the coupling constant
gs gp /\hbar c< 1.5× 10-24 at the
Compton wavelength λ = 10-3 m, the force (F) between
a 0.08× 0.08× 0.002 m3 block of α -quartz
and a 0.08× 0.08× 0.01 m3 copper block with a
separation being 0.5× 10-3 \mbox{m} in between, is
estimated from the published data at less than 4.64× 10-24 N, i.e. F < 4.64× 10-24 N. 相似文献
11.
Dao-Xin Liu 《中国物理 B》2023,32(1):10601-010601
We report an experimental demonstration of geopotential difference measurement using a pair of transportable $^{40}$Ca$^{+}$ optical clocks (TOC-729-1 and TOC-729-3) in the laboratory, each of them has an uncertainty of $1.3 \times 10^{-17}$ and an instability of $4.8 \times 10^{-15}/\sqrt{ \tau } $. Referenced to a stationary clock of TOC-729-1, the geopotential difference measurements are realized by moving TOC-729-3 to three different locations and the relevant altitude differences are measured with uncertainties at the level of 20 cm. After correcting the systematic shifts (including gravitational red shift), the two-clock frequency difference is measured to be $-0.7(2.2) \times 10^{-17}$, considering both the statistic $(1.0 \times 10^{-17})$ and the systematic $(1.9 \times 10^{-17})$ uncertainties. The frequency difference between these two clocks is within their respective uncertainties, verifying the reliability of transportable $^{40}$Ca$^{+}$ optical clocks at the low level of 10$^{-17}$. 相似文献
12.
L. Adiels G. Backenstoss I. Bergström S. Carius S. Charalambous M. D. Cooper Ch. Findeisen D. Hatzifotiadou M. Hugi A. Kerek H. O. Meyer P. Pavlopoulos J. Repond L. Tauscher D. Tröster M. C. S. Williams K. Zioutas 《Zeitschrift fur Physik C Particles and Fields》1987,35(1):15-19
The branching ratios of \(p\bar p\) annihilations into the neutral final states 2π0, π0γ, and 2γ are measured by stopping antiprotons in liquid hydrogen. They are \(B_{2\pi ^0 } = \left( {2.06 \pm 0.14} \right) \times 10^{ - 4} \) , \(B_{\pi ^0 \gamma } = \left( {1.74 \pm 0.22} \right) \times 10^{ - 5} \) , andB γγ<1.7×10?6 (95% c.l.). 相似文献
13.
In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of
14.
Florian Hartmann Wolfgang Kilian 《The European Physical Journal C - Particles and Fields》2014,74(9):1-6
A search for axioelectric absorption of solar axions produced in the \(p + d \rightarrow {^3\mathrm {He}}+\gamma (5.5~\mathrm {MeV})\) reaction has been performed with a BGO detector placed in a low-background setup. A model-independent limit on the combination of axion–nucleon and axion–electron coupling constants has been obtained: \(| g_{Ae}\times g_{AN}^3|< 1.9\times 10^{-10}\) for 90 % confidence level. The constraint of the axion–electron coupling constant has been obtained for hadronic axion with masses of (0.1–1) MeV: \(|g_{Ae}| \le (0.96 - 8.2)\times 10^{-8}\) . 相似文献
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We use the recent KamLAND observations to predict the solar antineutrino spectrum at some confidence limits. We find a scaling of the antineutrino probability with respect to the magnetic field profile—in the sense that the same probability function can be reproduced by any profile with a suitable peak field value—that can be utilized to obtain the general shape ofthe solar antineutrino spectrum. This scaling and the upper bound on the solar antineutrino event rate, which can be derived from the data, lead to: 1) an upper bound on the solar antineutrino flux and 2) the prediction of their energy spectrum. We get \(\phi _{\bar \nu } < 3.8 \times 10^{ - 3} \phi (^8 B)\) or \(\phi _{\bar \nu } < 5.5 \times 10^{ - 3} \phi (^8 B)\) at 95% C.L., assuming Gaussian or Poissonian statistics, respectively. For 90% C.L., these become \(\phi _{\bar \nu } < 3.4 \times 10^{ - 3} \phi (^8 B)\) and \(\phi _{\bar \nu } < 4.9 \times 10^{ - 3} \phi (^8 B)\). This provides an improvement by a factor of 3–5 with respect to the existing bounds. These limits are quite general and independent of the detailed structure of the magnetic field in the solar interior. 相似文献
17.
F. Eisele H. Filthuth V. Hepp W. Presser G. Zech 《Zeitschrift für Physik A Hadrons and Nuclei》1970,238(4):372-378
From about 2 × 106 measured ∑± decay's produced by stoppingK ? mesons in the 81 cm Saclay hydrogen bubble chamber about 140,000 ∑? →n π? and 20,000 ∑+ →nπ+ decays were selected for a lifetime measurement. We obtained: $$\begin{gathered} \tau _{\Sigma ^ + } = (0.795 \pm 0.010) \times 10^{ - 10} \sec \hfill \\ \tau _{\Sigma ^ - } = (1.485 \pm 0.022) \times 10^{ - 10} \sec . \hfill \\ \end{gathered} $$ 相似文献
18.
C. S. Fischer T. Goecke R. Williams 《The European Physical Journal A - Hadrons and Nuclei》2011,47(2):28
Using the Dyson-Schwinger and Bethe-Salpeter equations, we calculate the hadronic light-by-light scattering contribution to
the anomalous magnetic moment of the muon am\ensuremath a_\mu , using a phenomenological model for the gluon and quark-gluon interaction. We find am=(84 ±13)×10-11\ensuremath a_\mu=(84 \pm 13)\times 10^{-11} for meson exchange, and am = (107 ±2 ±46)×10-11\ensuremath a_\mu = (107 \pm 2 \pm 46)\times 10^{-11} for the quark loop. The former is commensurate with past calculations; the latter much larger due to dressing effects. This
leads to a revised estimate of am=116 591 865.0(96.6)×10-11\ensuremath a_\mu=116 591 865.0(96.6)\times 10^{-11} , reducing the difference between theory and experiment to ≃ 1.9s \sigma . 相似文献
19.
Vijender Singh Praveen Aghamkar Rajesh Kumar Malik 《Applied physics. B, Lasers and optics》2014,115(3):391-399
We report a large positive third-order optical nonlinearity of synthesized oligoazine derivatives (OADs) using z-scan technique at 532 nm by Q-switched Nd:YAG laser. Optical band gap of OADs shrinks with increasing repeated units. Origin of large cubic nonlinearity is in the extensive π-electron delocalization. We obtained the values of $\chi_{R}^{(3)} \approx (0.78 - 3.98) \times 10^{ - 11} \,{\text{esu}}$ and $\chi_{I}^{(3)} \approx (0.21 - 1.95) \times 10^{ - 11} \,{\text{esu}}$ in OADs. Moreover, values of optical nonlinearity of OADs show reasonable agreement with the theoretically predicted values. We have shown OADs could be used as good reverse saturable absorber and self-focusing materials. Optical limiting, due to reverse saturable absorption, has also been successfully demonstrated at 532 nm. 相似文献
20.
I. Alfter E. Bodenstedt W. Knichel J. Schüth 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):277-286
The E2/M1 multipole mixing parameters of cascade transitions inγ-vibrational bands of154Gd,166Er and168Er have been determined byγ-γ directional correlation measurements as: $$\begin{array}{l} \delta \left( {^{154} Gd\left( {3_\gamma ^ + \to 2_\gamma ^ + } \right)} \right) = - 4.3_{ + 2.1}^{ - 9.4} \\ \delta \left( {^{166} Er\left( {5_\gamma ^ + \to 4_\gamma ^ + } \right)} \right) = + 1.94_{ - 0.21}^{ + 0.23} \\ \end{array}$$ and $$\delta \left( {^{168} Er\left( {3_\gamma ^ + \to 2_\gamma ^ + } \right)} \right) = + 1.42_{ - 0.04}^{ + 0.04} $$ (with conversion data [15] taken into account) These data were used to deriveg(2+ γvib)?g(2+rot). The results, together withg-factors derived from direct measurements by IPAC and Mössbuer spectroscopy [10] or by use of transient fields [9, 31] exhibit a strong correlation between bothg-factors, i.e. ifg(2+rot) is largeg(2+ γvib) is small and vice versa. The most direct and most simple interpretation is the assumption of a more or less different density distribution of protons and neutrons in the nuclei. 相似文献
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